In mining operations, bolts are often used to support the roof of the mine. Typically, a bore is drilled into the rock formation that forms the mine roof, and then a mine roof bolt is placed in the bore and secured by a fast-curing resin material or other suitable substance. The roof bolt, which can be formed of wire strands woven or wound together to form a cable, includes a widened bearing plate that bears against a portion of the roof, thus holding a portion of the roof in place.
One approach for installing such bolts is to drill an over-sized bore into the rock and then insert one or more resin cartridges into the bore. The elongated cable portion of the mine roof bolt is then forced into the bore, and rotated. This process ruptures the resin cartridges and mixes the two resin components together within the space between the cable portion of the bolt structure and the over-sized bore.
Such roof bolts typically include a wedge barrel. The wedge barrel provides a bearing surface so that the tensile load carried by the elongated cable bolt can be suitably transferred to the bearing plate. The wedge barrel is commonly joined to the cable bolt by a plurality of wedges which are wedged between the cable itself and an inside tapered surface of the wedge barrel prior to installation of the roof bolt. Using a suitable tool, the wedge barrel is spun to rotate the cable within the bore as mentioned above. So configured, the bearing plate and wedge barrel can intrude upon the working space within the mine because they extend below the mine roof.